The compounds used in this invention and methods for their preparation are known in the art and are shown in U.S. Pat. No. 3,758,506, patented Sept. 11, 1973 to Jean Jacques Godfrold and Jean Eugene Thuillier assigned to C.E.R.P.H.A. In this patent, the above compounds, particularly the [2,3-dichloro-4-(2-thenoyl)phenoxy]-acetic acid or its pharmaceutically acceptable salts thereof are shown to be strong diuretic agents.